The objective is to bet big into slugs of tens and aces, and cut low cards out of play, not merely to get a positive count slug at the start of the shoe. It is just a logical extension of card counting.
As to indexes, you use the same strike numbers you use for a regular count system.
the shuffles are simple such as first deck merged completely with 4th, you know the count of the slug. I once played against a dealer who shuffled undealt cards seperate from the dealt thus I know exactly the count of the slug I tracked. The result was $52k a night...: )